Frequency-based communication system and method

ABSTRACT

A communication system includes multiple nodes of a time-sensitive network and a scheduler device. At least one of the nodes is configured to obtain a first signal that is represented in a frequency domain by multiple frequency components. The scheduler device generates a schedule for transmission of signals including the first signal within the time-sensitive network. The schedule defines multiple slots assigned to different discrete frequency sub-bands within a frequency band. The slots have designated transmission intervals. The nodes are configured to transmit the first signal through the time-sensitive network to a listening device such that the first signal is received at the listening device within a designated time window according to the schedule. At least some of the frequency components of the first signal are transmitted through the time-sensitive network within different slots of the schedule based on the frequency sub-bands assigned to the slots.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a national stage application, filed under 35 U.S.C.§ 371, of International Patent Application No. PCT/US2019/055120, filed8 Oct. 2019, which claims priority to U.S. Provisional Application No.62/758,791, filed 12 Nov. 2018. The entire disclosures of theseapplications are incorporated herein by reference.

FIELD

The subject matter described herein relates to communication networks.

BACKGROUND

The IEEE 802.1 Time-Sensitive Networking Task Group has created a seriesof standards that describe how to implement deterministic, scheduledEthernet frame delivery within an Ethernet network. Time-sensitivenetworking benefits from advances in time precision and stability tocreate efficient, deterministic traffic flows in an Ethernet network.Time-sensitive networks can be used in safety critical environments,such as control systems for automated industrial systems. In theseenvironments, timely and fast control of vehicles and/or machinery isneeded to ensure that operators and equipment at or near the vehiclesand/or machinery being controlled are not hurt or damaged.

Some known time-sensitive networks are scheduled in the time domainutilizing frame sizes and traffic flow latencies as schedulingconstraints. But, limiting the acceptable range of frame sizes andtraffic flow latencies may add complexity and/or unnecessarily constrainthe potential solutions of the scheduling device, especially when thetime-sensitive network communicates messages represented byfrequency-based acoustic signals. Furthermore, known time-sensitivenetworks are not scheduled based on the quality or fidelity of signalstransmitted through the time-sensitive network, and therefore thesignals exiting the time-sensitive network may fail to satisfy qualitystandards.

BRIEF DESCRIPTION

In one embodiment, a communication system includes a scheduler deviceincluding one or more processors configured to generate a schedule forcommunication of signals through nodes of a time-sensitive network thatare communicatively connected to each other via links of thetime-sensitive network. At least a first signal of the signals isrepresented in a frequency domain by multiple frequency components andreceived into the time-sensitive network from a publishing device. Theone or more processors are configured to generate the schedule byassigning multiple slots having designated transmission intervals todifferent discrete frequency sub-bands within a frequency band. Theschedule is generated to direct the nodes to communicate the firstsignal from the publishing device through the time-sensitive network toa listening device such that the first signal is received at thelistening device within a designated time window according to theschedule. At least some of the frequency components of the first signalare transmitted through the time-sensitive network based on thefrequency sub-bands assigned to the slots.

In one embodiment, a method includes generating a schedule fortransmission of signals within a time-sensitive network. The scheduledefines multiple slots assigned to different discrete frequencysub-bands within a frequency band and the slots have designatedtransmission intervals. The method also includes obtaining a firstsignal of the signals from a publishing device. The first signal isrepresented in a frequency domain by multiple frequency components. Themethod also includes transmitting the first signal through thetime-sensitive network to a listening device such that the first signalis received at the listening device within a designated time windowaccording to the schedule. At least some of the frequency components ofthe first signal are transmitted through the time-sensitive networkwithin different slots of the schedule based on the frequency sub-bandsassigned to the slots.

In one embodiment, a communication system includes a scheduler deviceincluding one or more processors configured to generate a schedule forcommunication of signals through nodes of a time-sensitive network thatare communicatively connected to each other via links of thetime-sensitive network. At least a first signal of the signals isrepresented in a frequency domain by multiple frequency components andreceived into the time-sensitive network from a publishing device. Theone or more processors are configured to generate the schedule byassigning multiple slots having designated transmission intervals todifferent discrete frequency sub-bands within a frequency band. Theschedule is generated to direct the nodes to communicate the frequencycomponents of the first signal through the time-sensitive network basedon the frequency sub-bands assigned to the slots such that the nodestransmit a first frequency component of the first signal within a firstslot of the slots that is assigned to a frequency sub-band that containsa frequency of the first frequency component and the nodes transmit asecond frequency component of the first signal within a second slot ofthe slots that is assigned to a different frequency sub-band thatcontains a frequency of the second frequency component.

BRIEF DESCRIPTION OF THE DRAWINGS

The present inventive subject matter will be better understood fromreading the following description of non-limiting embodiments, withreference to the attached drawings, wherein below:

FIG. 1 schematically illustrates one embodiment of a communicationsystem that includes a control system and a time-sensitive network;

FIG. 2 is a graph plotting an acoustic signal in both a frequency domainand a time domain according to an embodiment;

FIG. 3 is a graph illustrating a portion of a schedule for thetime-sensitive network according to an embodiment;

FIG. 4 depicts a portion of the schedule corresponding to a single slotover time according to an embodiment;

FIG. 5 shows sine waves produced by two speakers according to acousticsignals transmitted through the time-sensitive network as the frequencycomponents shown in FIG. 4; and

FIG. 6 illustrates a flowchart of one embodiment of a method forcommunicating messages in a time-sensitive network.

DETAILED DESCRIPTION

One or more embodiments of the inventive subject matter described hereinrelate to systems and methods that schedule the transmission of signalsin a time-sensitive network in the frequency domain to improve thetransmission of acoustic signals. For example, the time-sensitivenetwork is scheduled to transmit acoustic signals that have a frequencycontent, such as but not limited to audio compressed signals,ultrasound, vibrations, acoustic phenomena, or the like. In one or moreembodiments, a control device of the time-sensitive network, such as ascheduler device, is configured to account for signal fidelity of thesignals when scheduling the time-sensitive network. For example, thescheduler may schedule the time-sensitive network based on one or moresignal fidelity targets, instead of (or in addition to) frame size andtraffic flow latency constraints. The signal fidelity target may be ametric that indicates a general quality of the signal that is outputfrom the time-sensitive network. More specifically, the signal fidelitytarget can represent a degree of correspondence between a state orquality of a given signal exiting the time-sensitive network and thestate or quality of the same signal entering the time-sensitive network.

At least one technical effect of the subject matter described hereinprovides for reduced complexity in the scheduling of time-sensitivenetworks by scheduling in the frequency domain based on frequencycomponents of acoustic signals instead of scheduling in the time domain.Another technical effect of scheduling in the frequency domain isimproved signal fidelity because the time-sensitive network functions asa low pass filter. For example, by scheduling the transmission ofsignals along different specific frequency sub-bands in a bandwidth,signal components having frequencies outside of the scheduled frequencysub-bands may be filtered out (e.g., not transmitted). The frequenciesthat are filtered out may be attributable to background noise,interference, minor components of the signals, and/or the like. Thefiltering of signal components may reduce the complexity and amount ofinformation transmitted over the time-sensitive network versustransmitting all components of the received signals, which may improvethe reliability and throughput of the network. Another technical effectof scheduling in the frequency domain based on the signal fidelitytarget, instead of frame size and/or latency periods, is an increase inthe number of potential solutions that may be analyzed by the schedulerdevice when or while generating the schedule. For example, by schedulingin the frequency domain, it may be permissible for signals that arecommunicated through the time-sensitive network to have periodiclatencies at nodes that would otherwise violate a latency constraint.

FIG. 1 schematically illustrates one embodiment of a communicationsystem 100 that includes a control system 107 and a time-sensitivenetwork 109. The control system 107 controls communications through thetime-sensitive network 109. The components shown in FIG. 1 representhardware circuitry that includes and/or is connected with one or moreprocessors (e.g., one or more microprocessors, field programmable gatearrays, and/or integrated circuits) that operate to perform thefunctions described herein. The components of the communication system100 can be communicatively coupled with each other by one or more wiredand/or wireless connections. Not all connections between the componentsof the communication system 100 are shown herein. The time-sensitivenetwork 109 can be configured to operate according to one or more of thetime-sensitive network standards of IEEE, such as the IEEE 802.1AS™-2011Standard, the IEEE 802.1Q™-2014 Standard, the IEEE 802.1Qbu™-2016Standard, and/or the IEEE 802.3br™-2016 Standard.

The time-sensitive network 109 includes several node devices 105(hereafter referred to as nodes) formed of network switches 104 and/orassociated clocks 112 (“clock devices” in FIG. 1). While only threenodes 105 are shown in FIG. 1, the communication system 100 can beformed of many more nodes 105 that may be distributed over a largegeographic area. The switches 104 of the nodes 105 may include orrepresent electrical switches, routers, bridges, hubs, and/or the like.The nodes 105 are communicatively connected to one another viacommunication links 103 (referred to herein as links 103). The links 103may include or represent physical communication pathways, such as copperwires and/or cables, optical wires and/or cables, Ethernet links, andthe like. Optionally, the links 103 may represent wireless communicationpathways.

The time-sensitive network 109 can be an Ethernet network thatcommunicates data frames (or packets) as signals along traffic flowpaths 120 between communication devices 106. A signal referred to hereincan be a message formed of many data packets or frames, several datapackets or frames making us less than an entire message, or anindividual data packet or frame. The traffic flow paths 120 can bedefined by the nodes 105 and the links 103 that are in the differentpaths 120. For example, a data frame may be transmitted through a path120 from a first link 103 to a second link 103 through a node 105 thatconnects the first and second links 103, with the path 120 formed of thefirst and second links 103 and the node 105. The data frames can be sentalong different paths 120 according to a schedule of the time-sensitivenetwork 109. The paths 120 may partially overlap or intersect eachother. For example, two paths 120 may partially overlap when the paths120 share at least one of the same links 103. Two paths 120 mayintersect each other when the paths 120 share at least one of the samenodes 105. The schedule restricts which data frames can be communicatedby each of the nodes 105 along one or more (or all) paths 120 atdifferent times.

Different data frames (e.g., signals) can be communicated at differentrepeating scheduled time periods based on traffic classifications of theframes. Some data frames represent messages that are classified astime-critical traffic (referred to herein as time-critical messages)while other data frames represent messages classified as best-efforttraffic (referred to herein as best-effort messages). The time-criticalmessages have a higher priority than the best effort messages. Thetime-critical messages may be required to be communicated at or withindesignated periods of time to ensure the safe operation of a poweredsystem, such as industrial machinery or a vehicle (e.g., locomotive,automobile, off-road truck, marine vessel, aircraft, or the like). If atime-critical message is not received within the designated time periodor window, the lack of timely receipt of the time-critical message mayrisk harm to people and/or damage to the system or surroundings. Thebest-effort messages include data frames that are not required to ensurethe safe operation of the powered system, but that are communicated forother purposes (e.g., monitoring operation of components of the poweredsystem).

The communication devices 106 that communicate via the time-sensitivenetwork 109 may be computers, sensors, servers, control devices, or thelike. In one embodiment, the devices 106 are disposed onboard one ormore vehicles. For example, a first communication device 106A of thedevices 106 may be a different type of device from a secondcommunication device 106B and/or a third communication device 106C. Thedevice 106 that generates or inputs a message (defined by one or moresignals) into the time-sensitive network 109 for communication toanother device 106 is referred to as a publishing device (or publisher).The device 106 that receives the message output from the time-sensitivenetwork 109 is referred to as a listening device (or listener). Forexample, a first communication device 106A may be the publishing deviceand a second communication device 106B may be the listening device for agiven message transmitted via the time-sensitive network 109.Optionally, one or more of the devices 106 may be able to function asboth publishing devices and listening devices to enable bi-directionalcommunications between the devices 106 through the time-sensitivenetwork 109. Although three devices 106A-C are shown in FIG. 1, thecommunication system 100 may enable more than three devices 106 (e.g.,dozens, hundreds, or thousands), or only two devices 106, to reliablycommunicate with one another.

Optionally, the first and second communication devices 106A, 106B (e.g.,the publishing device and the listening device) may be disposed on thesame vehicle. Alternatively, the first communication device 106A isdisposed on a first vehicle and the second communication device 106B isremote from the first vehicle (although connected to the firstcommunication device 106A via the time-sensitive network 109). Forexample, the second communication device 106B may be dispose onboard adifferent, second vehicle than the first communication device 106A. Inanother example, the second communication device 106B may be disposed atan off-board location, such as at a wayside device or the like.

The control system 107 includes a time-aware scheduler device 102, acentralized network configurator device 108, and a grandmaster clockdevice 110. The scheduler device 102 generates a schedule that instructseach node 105 to transmit an Ethernet data frame along a predefined path120 at a prescheduled time, creating deterministic traffic flows whilesharing the same media with legacy, best-effort Ethernet traffic. Thetime-sensitive network 109 has been developed to support hard, real-timeapplications where delivery of frames of time-critical traffic must meettight schedules without causing failure, particularly in life-criticalvehicular and/or industrial control systems. The scheduler device 102computes the schedule, and the schedule is installed at each node 105 inthe time-sensitive network 109 or some, but not all, nodes 105. Thisschedule dictates when different types or classification of signals arecommunicated by the switches 104 of the nodes 105. For example, theschedule may dictate that a given switch 104 transmits a time-criticalmessage at a first time or interval, and the switch 104 transmits a besteffort message at a different, second time or interval. The schedule mayalso dictate arrival time windows or periods within which the dataframes are required to be received at a designated listening device,such as the communication device 106B.

The scheduler device 102 may solve a system of scheduling equations tocreate the schedule for the switches 104 of the nodes 105 to sendEthernet frames in a time-sensitive manner through the communicationsystem 100. This schedule may be subject to various constraints, such asthe topology of the time-sensitive network 109, the speed ofcommunication by and/or between switches 104 in the time-sensitivenetwork 109, the amount of Ethernet frames to be communicated throughdifferent switches 104, etc. This schedule can be created to avoid twoor more Ethernet frames colliding with each other at a switch 104 (e.g.,to prevent multiple frames from being communicated through the sameswitch 104 at the same time).

The scheduler device 102 may be formed from hardware circuitry that isconnected with and/or includes one or more processors that generate theschedule for the time-sensitive network 109. The scheduler device 102 issynchronized with the grandmaster clock device 110 of the control system107. The grandmaster clock device 110 includes a clock to which theclocks 112 of the nodes 105 are synchronized.

The centralized network configurator device 108 (referred to herein asconfigurator device 108) of the control system 107 is comprised ofsoftware and/or hardware that has knowledge of the physical topology ofthe time-sensitive network 109 as well as the traffic flow paths 120.The configurator device 108 can be formed from hardware circuitry thatis connected with and/or includes one or more processors that determineor otherwise obtain the topology information from the nodes 105 and/oruser input.

The physical topology of the time-sensitive network 109 maps thehardware of the time-sensitive network 109, including the locations(e.g., absolute and/or relative locations) of all of the nodes 105, thecommunication devices 106, and the links 103 that connect the nodes 105and the communication devices 106. The topology can also identify whichof the nodes 105 are directly coupled with other nodes 105 and/or thecommunication devices 106 via links 103. The locations of the hardwarecomponents can be used to determine distances between the hardwarecomponents, which may be utilized by the scheduler device 102 whenscheduling flow paths 120 for conveying data frames within designatedtime windows. The physical topology may also include additionalinformation about the hardware within the time-sensitive network 109,such as the types of hardware (e.g., part numbers), instructions forcommunicating with the various nodes 105 and other hardware, and/or thelike.

The topology information may be stored in a database and accessed by theconfigurator device 108. Alternatively, the configurator device 108 maygenerate the topology information by communicating with the nodes 105 inthe time-sensitive network 109 to determine the types and locations(relative or absolute) of the nodes 105. The configurator device 108 canprovide this topology information to the scheduler device 102, whichuses the topology information to determine the schedules forcommunication of messages between the communication devices 106. Theconfigurator device 108 and/or scheduler device 102 can communicate theschedule to the different nodes 105.

The hardware circuitry and/or processors of the configurator device 108can be at least partially shared with the hardware circuitry and/orprocessors of the scheduler device 102. For example, one or moreprocessors and associated circuitry may be configured to perform theoperations of both the configurator device 108 and the scheduler device102 as described herein. Alternatively, the one or more processors ofthe configurator device 108 are all discrete and separate from the oneor more processors of the scheduler device 102. In yet anotherembodiment, a subset of processors of the configurator device 108 isshared in common with the scheduler device 102, and/or a subset ofprocessors of the scheduler device 102 is shared in common with theconfigurator device 108.

The control system 107 (e.g., the scheduler device 102) may communicatewith the time-aware nodes 105 (e.g., the switches 104 with respectiveclocks 112) through a network management protocol. For example, a linklayer discovery protocol can be used to exchange information between thenodes 105 and the scheduler device 102. The time-aware nodes 105 mayimplement a control plane element that forwards the commands from thescheduler device 102 to their respective hardware. The configuratordevice 108 may poll the nodes 105 and the communication devices 106 toretrieve topology information of the time-sensitive network 109 via thenetwork management protocol, and the topology information may beprovided to the scheduler device 102.

In one or more embodiments, the communication system 100 is disposed onone or more vehicles of a vehicle system. Alternatively, thecommunication system 100 may not be disposed onboard any vehicle. InFIG. 1, the communication system 100 is disposed on a locomotive 150(e.g., a propulsion-generating rail vehicle) of a rail vehicle system.The locomotive 150 may be mechanically and communicatively coupled toanother locomotive or a non-propulsion generating rail car. For example,the locomotive 150 may be communicatively coupled to another locomotiveby a wired connection, such as a 27-pin trainline cable. The componentsof the communication system 100, such as the nodes 105, the configuratordevice 108, the scheduler device 102, and the communication devices 106,may be entirely disposed onboard the locomotive or the rail vehiclesystem, such that all components are disposed onboard the same vehicleor onboard multiple vehicles that travel together along routes as avehicle system. Alternatively, at least some of the components of thecommunication system 100, such as the configurator device 108 and/or thescheduler device 102, may be disposed off-board the rail vehicle system.

While the communication system 100 is shown as being disposed onboard alocomotive 150 of a rail vehicle system, alternatively, thecommunication system 100 may be disposed onboard another type of vehiclesuch as an automobile, a marine vessel, a mining vehicle, or anotheroff-highway vehicle (e.g., a vehicle that is not legally permitted orthat is not designed for travel along public roadways). In yet anotherembodiment, the communication system 100 may be installed off-board avehicle, such as installed in an industrial setting (e.g., factory,manufacturing plant, or the like). For example, the communication system100 optionally may be used to provide network communications in systemsother than vehicle networks.

The communication devices 106 may provide data and/or control signalsthat are important for the safe operation of the rail vehicle system.The communication devices 106 may represent one or more of tractionmotor controllers, an engine control unit, an auxiliary load controller,an input/output device, sensors, and/or the like. The time-sensitivenetwork 109 is utilized to ensure precise, uninterrupted communicationbetween these devices to ensure safe operation of the locomotive 150.For example, the communications between these devices that are used forcontrolling the movement of the locomotive 150 may be designated astime-critical messages that have a greater priority than best effortmessages between different, less critical communication devices.

In FIG. 1, the first communication device 106A may be an input/outputdevice. The input/output device 106A may represent one or more devicesthat receive input from an operator onboard the locomotive 150 and/orthat present information to the operator. The input/output device 106Acan represent one or more touchscreens, keyboards, styluses, displayscreens, lights, speakers, or the like.

The second communication device 106B may be a traction motor controllerthat controls operation of traction motors 152 of the locomotive 150.The traction motor controller 106B represents hardware circuitry thatincludes and/or is connected with one or more processors (for example,one or more microprocessors, field programmable gate arrays, and/orintegrated circuits) that generate control signals for controlling thetraction motors 152. For example, based on or responsive to a throttlesetting selected by an operator input via the input/output device 106Aand communicated to the traction motor controller 106B via thetime-sensitive network 109, the traction motor controller 106B maychange a speed at which one or more of the traction motors 152 operateto implement the selected throttle setting.

The third communication device 106C may be an engine control unit, anauxiliary load controller, a sensor, or the like. For example, each ofthe engine control unit and the auxiliary load controller representshardware circuitry that includes and/or is connected with one or moreprocessors (for example, one or more microprocessors, field programmablegate arrays, and/or integrated circuits) that generate control signals.The control signals generated by the engine control unit arecommunicated to an engine of the locomotive 150 (for example, based oninput provided by the input/output device 106A) in order to controloperation of the engine of the locomotive 150. The control signalsgenerated by the auxiliary load controller are communicated to one ormore auxiliary loads of the locomotive 150 to control operation of theone or more auxiliary loads. The auxiliary loads may consume electriccurrent without propelling movement of the locomotive 150. The auxiliaryloads can include, for example, fans or blowers, battery chargers,lights, and/or the like. The third communication device 106C is referredto as the engine control unit 106C herein.

To ensure that communications between the communication devices 106(e.g., input/output devices, traction motor controllers, engine controlunits, auxiliary load controllers, sensors, and/or the like) are sentand/or received in time, the scheduler device 102 schedules thecommunications through the time-sensitive network 109. Communicatingthrough the time-sensitive network 109 ensures, for example, that achange to a throttle setting received by the input/output device isreceived by the traction motor controllers within a designated period oftime, such as within a few milliseconds. In contrast to a conventionalEthernet network (operating without a time-sensitive network) thatcommunicates data frames or packets in a random manner, thetime-sensitive network 109 communicates the data frames or packetsaccording to the type or category of the data or information beingcommunicated to ensure that the data is communicated within designatedtime periods or at designated times. With respect to some vehiclecontrol systems, the late arrival of data can have significantlynegative consequences, such as an inability to slow or stop movement ofa vehicle in time to avoid a collision.

As described above, the time-sensitive network 109 may be an Ethernetnetwork that prioritizes communications and dictates when certaincommunications occur to ensure that certain data frames or packets arecommunicated within designated time periods or at designated times. Thecommunications between or among some of the communication devices 106may include time sensitive information or data. For example, dataindicative of a change in a brake setting may need to be communicatedfrom the input/output device 106A to the traction motor controller 106Bwithin several milliseconds of being sent by the input/output device106A into the network 109. The failure to complete this communicationwithin the designated time limit or period of time may prevent the railvehicle system from braking in time. Non-time sensitive communicationsmay be communications that do not necessarily need to be communicatedwithin a designated period of time, such as communication of a locationof the vehicle system from a global positioning system (GPS) receiver, ameasurement of the amount of fuel from a fuel sensor, etc. Thesenon-time sensitive communications may be designated as best effortcommunications that are a lower priority than the time sensitivecommunications.

Best effort communications may be communicated within the time-sensitivenetwork 109 when there is sufficient bandwidth in the network 109 toallow for the communications to be successfully completed withoutdecreasing the available bandwidth in the network 109 below a bandwidththreshold needed for the communication of time sensitive communicationsbetween publishing devices and listening devices. For example, if 70% ofthe available bandwidth in the network 109 is needed at a particulartime to ensure that communications with the engine control unit 106C andtraction motor controller 106B successfully occur, then the remaining30% of the available bandwidth in the network 109 may be used for othercommunications, such as best effort communications with the auxiliaryload controller. The bandwidth threshold may be a user-selected ordefault amount of bandwidth. The communication of best effortcommunications may be delayed to ensure that the time sensitivecommunications are not delayed.

The priority statuses of different types of communications may be set bythe control system 107 and/or the operator of the locomotive 150. Forexample, the control system 107 may designate that all communications toand/or from the engine control unit 106C, the traction motor controller106B, the input/output device 106A, and sensors that monitor engineconditions, traction motor conditions, and brake conditions are timesensitive communications, and communications to and/or from onboarddisplay devices, the auxiliary load controller, and auxiliary devicesare best effort communications. Optionally, the type of informationbeing communicated by these devices may determine the type ofcommunications. For example, the control system 107 may establish thatcontrol signals (e.g., signals that change operation of a device, suchas by increasing or decreasing a throttle of a vehicle, applying brakesof a vehicle, etc.) communicated to the engine control unit 106C and/ortraction motor controller 106B may be time sensitive communicationswhile status signals (e.g., signals that indicate a current state of adevice, such as a location of the locomotive 150) communicated from theengine control unit 106C and/or traction motor controller 106B are besteffort communications.

According to one or more embodiments described herein, thetime-sensitive network 109 is configured to communicate acoustic signalsbetween the communication devices 106 in addition to, or as analternative to, conventional electrical signals. The acoustic signalsmay each be represented by multiple frequency components, such ascomponents at different frequencies within a frequency band or spectrum.The acoustic signals may include audio signals, audible sound signals,ultrasound signals, infrasound or low frequency signals, vibrations,and/or the like. An audio signal may represent a signal in an audioand/or video application. Audible sounds are in the frequency rangeperceptible to an ordinary person. The frequencies of the ultrasoundsignals and the infrasound signals are greater and less than,respectively, frequencies perceptible to the ordinary person. Thevibration signals may refer to the vibrations of various componentsonboard the locomotive 150, such as the engine.

FIG. 2 is a graph 200 plotting an acoustic signal 202 in both afrequency domain and a time domain according to an embodiment. The graph200 has a frequency axis 204, a time axis 206, and an amplitude axis208. The acoustic signal 202 can be represented in the time domain as asingle waveform 210 that has multiple different amplitude peaks andmultiple different amplitude valleys over time. The acoustic signal 202can also be represented in the frequency domain as multiple frequencycomponents 212. The acoustic signal 202 in the frequency domain showshow much of the signal 202 lies within different frequency bands. Thefrequency components 212 have different frequencies, and therefore arespaced apart along the frequency axis 204 within different frequencybands. The acoustic signal 202 has three frequency components 212 in theillustrated embodiment, but other acoustic signals may have only two orat least four frequency components. When viewed in the time domain, eachof the frequency components 212 is a sine wave 214 with a correspondingamplitude and period (e.g., frequency). In the frequency domain, thefrequency components 212 can be represented by bars 218. For example, ata specific time 216, the three frequency components 212 have differentfrequencies (as represented by spaced apart locations of bars 218 alongthe frequency axis 204) and different amplitudes (as represented by thedifferent heights of the bars 218).

The acoustic signal 202 is a combination of the frequency components212. Each of the frequency components 212 may be defined by a frequency,an amplitude, and/or a phase (e.g., phase shift). Different frequencycomponents 212 may have different frequencies, amplitudes, and/orphases. The frequency components 212 may be represented as complexnumbers including an amplitude (e.g., magnitude) of the component 212and relative phase of the wave (e.g., angle) at a given frequency.

On the locomotive 150, the acoustic signal 202 or other acoustic signalsmay represent a signature vibration of the engine that is monitoredand/or measured by a sensor. The acoustic signal 202 or other acousticsignals may represent a phase and/or frequency of electrical currentconveyed to or from the traction motors 152 (shown in FIG. 1). Theacoustic signal 202 or other acoustic signals may represent a voicecommand input by an operator utilizing a microphone of the input/outputdevice 106A (shown in FIG. 1). The acoustic signal 202 or other acousticsignals may represent audio and/or video content captured by a sensorand/or camera onboard the locomotive 150.

FIG. 3 is a graph 300 illustrating a portion of a schedule 306 for thetime-sensitive network 109 according to an embodiment. The graph 300 hasa vertical axis 302 that represents a frequency band 308 or spectrum.The graph 300 also has a horizontal axis 304 representing time. Theschedule 306 may be generated by the scheduler device 102 (shown in FIG.1). In an embodiment, the scheduler device 102 generates the schedule306 in the frequency domain. The schedule 306 dictates that differentfrequency components 212 of one or more signals (e.g., the signal 202shown in FIG. 2) are transmitted through the time-sensitive network 109at different time intervals. FIG. 3 shows five frequency components 212,identified as FC₁, FC₂, FC₃, FC₄, and FC₅. All five frequency components212 optionally may be components of the same acoustic signal.Alternatively, the five frequency components 212 may represent at leasttwo different acoustic signals.

In an embodiment, the schedule 306 defines multiple slots 310 that areassigned to different frequency sub-bands within the frequency band 308.The frequency sub-bands are discrete from each other, such that theslots 310 do not have overlapping sub-bands. The schedule 306 definesfive slots 310 in FIG. 3, which are identified as 310A, 310B, 310C,310D, 310E, but the schedule 306 may have any number of slots 310. Forexample, the slot 310B is assigned to a frequency sub-band betweenfrequencies ii and iii in FIG. 3, which is a frequency range. In anon-limiting example, the frequency ii may represent 50 Hz and thefrequency iii represents 100 Hz, such that the slot 310B is assigned tothe frequency sub-band from 50 Hz to 100 Hz. The scheduler device 102may assign the frequency sub-bands to the different slots 310 during thescheduling process. Optionally, at least some of the frequency sub-bandsassigned to the slots 310 may have different widths (e.g., differentsizes or ranges between the corresponding two outer frequencies). Forexample, the slots 310C and 310E are assigned to respective sub-bandsthat have greater widths than the respective sub-bands assigned to slots310A, 310B, and 310D. Alternatively, all of the slots 310 may beassigned to frequency sub-bands having the same widths although spacedapart along the frequency band 308.

The schedule 306 designates that the different slots 310 have differenttransmission intervals 314. The transmission intervals 314 representdesignated times or time windows at which a particular signal or dataframe is transmitted by the nodes 105 (shown in FIG. 1) of thetime-sensitive network 109. For example, in the schedule 306 shown inFIG. 3, the slot 310A has a transmission interval 314 between times t₃and t₄. Therefore, a node 105 may gate (e.g., not transmit) a signal ordata frame that is within the slot 310A until after time t₃, at whichthe node 105 transmits the signal or data frame to a subsequent node 105or to a listening device along the path 120 according to the schedule.The node 105 also gates similar signals within the slot 310A after timet₄ until the transmission cycle repeats. The slot 310B has a firsttransmission interval 314 between times 0 and t₁ and a secondtransmission interval 314 between times t₅ and t₆. Optionally, thetransmission intervals 314 may be cyclical. For example, the entiretransmission period from time 0 to t₅ may repeat such that thetransmission interval 314 between times t₅ and t₆ may be a repeat of theinterval 314 between times 0 and t₁. The transmission intervals 314according to the schedule may have the same durations, or at least someof the transmission intervals 314 may have longer durations than othertransmission intervals 314.

In at least one embodiment, at least some of the frequency components212 of the signal 202 (shown in FIG. 2) are transmitted through thetime-sensitive network 109 (shown in FIG. 1) within different slots 310of the schedule 306 based on the frequency sub-bands assigned to theslots 310. The frequency components 212 may be transmitted within slots310 that are assigned to sub-bands that correspond to the frequencies ofthe frequency components 212. For example, a frequency component 212 ofthe signal 202 that has a frequency of 207 Hz may be transmitted withina slot 310 assigned to a frequency sub-band that contains 207 Hz, suchas a sub-band from 200 Hz to 250 Hz. In FIG. 3, a first frequencycomponent 212 (“FC1”) is transmitted within the slot 310B, such that thefirst frequency component 212 has a transmission interval 314 betweentimes 0 and t₁. A second frequency component 212 (“FC2”) of the samesignal 202 has a greater frequency than the first frequency componentand is transmitted within the slot 310E. For example, the frequency ofthe second frequency component 212 may be 991 Hz, which is containedwithin the frequency sub-band 310E. A third frequency component 212(“FC3”) of the same signal 202 has a frequency between the first andsecond components, and is transmitted within the slot 310D.

The schedule 306 may stagger the transmission intervals 314 of differentfrequency components 212 such that one frequency component 212 of asignal may be transmitted by the nodes 105 at different times than thenodes 105 transmit another frequency component 212 of the same signal ora different signal. As shown in FIG. 3, the three frequency components212 (FC1 through FC3) of the same signal 202 are transmitted atdifferent transmission intervals 314. Therefore, these three frequencycomponents 212 may arrive at the designated listening communicationdevice 106 at slightly different (e.g., staggered) times. According toat least one embodiment, the different transmission intervals 314 haverelatively short durations, such as on the order of microseconds. Due tothe short durations, the staggered frequency components 212 are able tobe merged and processed at the listening device without a person beingable to perceive any offset. For example, if the listening device is aspeaker of the input/output device 106A (shown in FIG. 1), the staggeredfrequency components 212 of the signal 202 can be reconstructed andoutput by the speaker without a person being able to comprehend anynoise or signal degradation caused by a delay between the frequencycomponents 212. The nature of the time-sensitive network 109 ensuresthat the various frequency components 212 of the signal 202 are receivedon time within a designated time window according to the schedule. Theuse of the time-sensitive network 109 to transmit frequency-basedsignals (such as vibration signals, audio signals, ultrasound signals,and the like) according to a precise schedule may make buffering at thelistening device 106 unnecessary.

Optionally, the scheduler device 102 may schedule the time-sensitivenetwork 109 in the frequency domain such that the time-sensitive network109 functions as a low pass filter. The filter may be used to filter out(e.g., not transmit) certain frequency components of the signals. Forexample, certain frequencies of the signals may be attributable tobackground noise, interference, cross-talk, or the like. The signals mayalso contain frequencies that are unnecessary, such as frequencycomponents of audio signals that are outside of the audible frequencyrange that can be heard by ordinary persons or frequency components thatare masked by other frequencies and are therefore unintelligible. Thetime-sensitive network 109 can be used to filter out such frequencycomponents that are associated with background, interference, orunnecessary frequencies from the frequency components of the signalsthat are transmitted through the network 109. This filtering reduces theamount of data transmitted through the time-sensitive network 109,improving the throughput thereof.

For example, the scheduler device 102 may utilize the time-sensitivenetwork 109 as a filter by assigning the frequency sub-bands to theslots 310 such that the assigned sub-bands represent less than anentirety of the frequency band 308. For example, as shown in FIG. 3, thesub-bands between frequencies i and ii, between frequencies v and vi,and between frequencies ix and x are unassigned to the slots 310.Frequency components of the signals that have frequencies containedwithin the unassigned sub-bands may not be transmitted through thenetwork 109 to the listening device 106. These frequency components arefiltered out.

The scheduler device 102 may assign the frequency sub-bands to the slots310 based on an analysis of one or more signals that would betransmitted through the time-sensitive network 109. For example, thescheduler device 102 may analyze a dynamic range of one or more signalsto identify various frequency components of the signals. Based on theanalysis, the scheduler device 102 may select certain frequencies thatare unnecessary to represent the one or more signals, such asfrequencies determined to be attributable to noise or interference andfrequencies that are masked or outside of a perceptible range. Afterselecting the frequencies that are unnecessary to represent the one ormore signals, the schedule device 102 generates the schedule 306 suchthat these frequencies are not assigned to the slots 310.

In an embodiment, the frequency components 212 transmitted through thetime-sensitive network 109 may be encoded within Ethernet data frames.For example, the frequency components 212 may be digitally encodedwithin frames. The Ethernet frames include data that may represent thefrequency, amplitude, and/or phase of each frequency component 212encoded therein. Optionally, the six boxes representing frequencycomponents 212 shown in FIG. 3 may be six different Ethernet data framestransmitted through the network 109. Each data frame may include asingle frequency component 212. Alternatively, at least some data framesmay encode multiple frequency components 212 in a single frame.

In one or more embodiments, the scheduler device 102 generates theschedule 306 based on a signal fidelity target. The signal fidelitytarget may be a metric that indicates a general quality of the signalthat is output from the time-sensitive network 109. For example, thesignal fidelity target may represent a degree of correspondence betweena state or quality of a given signal exiting the time-sensitive network109 and the state or quality of the same signal entering thetime-sensitive network 109. The signal fidelity may be determined bycomparing the signal at the state provided by the publishing device 106to the same signal at the state provided by the network 109 to thelistening device 106. Filtering out certain frequencies of the signal toimprove the throughput of the time-sensitive network 109 may negativelyaffect the signal fidelity because the outgoing signal differs from theincoming signal by at least the filtered out components. Therefore,there may be a tradeoff associated with filtering out components of thesignals. Reduced filtering may improve the signal fidelity of thetransmitted signals as the cost of reducing network throughput andincreasing the load on the network 109.

The scheduler device 102 may obtain a designated signal fidelity target.The signal fidelity target may be stored in a memory and accessed by thescheduler device 102. For example, the signal fidelity target may bebased on a standard or regulation. Alternatively, the signal fidelitytarget may be selected by an operator using the input/output device 106A(shown in FIG. 1), and the operator selection may be received by thescheduler device 102. Upon obtaining the signal fidelity target, thescheduler device 102 utilizes the signal fidelity target as a constraintand schedules the time-sensitive network 109 to satisfy the signalfidelity target. The scheduler device 102 may base the assignment of thefrequency sub-bands to the slots 310 on the signal fidelity target. Forexample, the scheduler device 102 may assign the slots 310 to asufficient number and size of frequency sub-bands in the frequency band308 to satisfy the signal fidelity target. Increasing the number and/orsize of sub-bands assigned to the slots 310 may reduce the number offrequency components of the signals that are filtered out by thetime-sensitive network 109, thereby increasing the signal fidelity. Inan embodiment, the scheduler device 102 assigns the frequency sub-bandsto the slots 310 such that the signal fidelity achieved by the network109 is at or only slightly greater than the designated signal fidelitytarget. For example, if it is determined that a potential schedule doesnot satisfy the signal fidelity target, then the potential schedule ismodified and/or another potential is generated to increase the signalfidelity of the network 109. The schedule may be modified to increasethe signal fidelity by increasing the number of sub-bands assigned tothe slots 310 and/or the widths (e.g., sizes) of the sub-bands assignedto the slots 310. As a result, the network 109 is scheduled to satisfythe designated signal fidelity target, but the network 109 can still actas a low pass filter to filter out some unnecessary frequencycomponents.

In an embodiment, the scheduler device 102 generates the schedule basedon the designated signal fidelity target, which is a frequency-basedconstraint, without utilizing time-based constraints such as a framesize limit and/or a periodic latency limit. For example, typicalEthernet networks may be scheduled according to various constraints,such as the topology, requested flow latency, frame sizes, and/or thelike. But, the scheduler device 102 optionally may not utilize framesize or latency as constraints when generating the schedule 306 for thefrequency-based communication of signals through the time-sensitivenetwork 109. By not limiting the frame sizes and/or latency, thescheduler device 102 may be able to generate a schedule 306 insatisfaction of the designated signal fidelity target that would nothave been possible if the frame size, periodic latency, and/or otherconstraints were applied. For example, the schedule 306 that isgenerated may have one or more frame sizes that would be outside of thepermissible frame size limit if the frame size constraint was applied.

In an embodiment, the time-sensitive network 109 is configured tocombine the various frequency components 212 of a given signal after thefrequency components 212 are transmitted through the network 109. Forexample, a node 105 of the time-sensitive network 109 that iscommunicatively coupled to the designated listening device 106 maycombine the frequency components 212 to form an intact (e.g.,reconstructed) signal 202. The node 105 then transmits the intact signal202 to the listening device 106 for the listening device 106 to processthe signal. For example, combining the frequency components 212 toreconstruct the intact signal 202 may convert the frequency-basedrepresentation of the signal to a time-based representation of thesignal 202. Optionally, a Fourier transform or the like may be appliedto convert the signal 202. In an alternative embodiment, the listeningdevice 106, not the node 105 communicatively coupled to the listeningdevice 106, is configured to combine the frequency components 212 toreconstruct the signal 202.

In one or more embodiments, the scheduler device 102 may dynamicallyupdate the schedule 306 during the operation of the time-sensitivenetwork 109. For example, after some signals are transmitted through thetime-sensitive network 109, the scheduler device 102 may monitor thefidelity of the signals and other parameters. The scheduler device 102may be configured to modify or update the schedule 306 based on themonitored parameters in order to improve the signal fidelity or thelike. The scheduler device 102 modifies the schedule 306 by adjusting awidth (e.g., size) of the frequency sub-band assigned to one or more ofthe slots 310, assigning additional frequency sub-bands to slots 310,assigning fewer frequency sub-bands to slots 310, altering thetransmission intervals 314 of the slots 310, altering the order in whichthe frequency components 212 are transmitted, adjusting the traffic flowpaths 120 through the network 109, and/or the like. For example, if themonitored signal fidelity drops below the designated signal fidelitytarget, the scheduler device 102 may increase the width (e.g., size) ofat least one of the assigned frequency sub-bands which may reduce theportion of the signals that are filtered out, improving the signalfidelity.

The signals received by the listening devices 106 onboard the locomotive150 (shown in FIG. 1) may be used to control the movement of the railvehicle system. For example, the signal 202 (shown in FIG. 2) mayrepresent a measurement of a component onboard the locomotive 150, suchas the engine, traction motors 152, or an auxiliary load. Alternatively,the signal may be represent a command received from an operator usingthe input/output device 106A or a command received from another devicelocated on another vehicle system or at a dispatch center. The signal202 optionally may be classified as a time-critical message, oralternatively as a best effort message. Responsive to receiving thesignal 202, the locomotive 150 may be controlled to slow or stopmovement. For example, the brakes of the locomotive 150 may beautomatically applied upon receipt of the signal 202 at the listeningdevice.

FIG. 4 depicts a portion of the schedule 306 corresponding to a singleslot 310 over time according to an embodiment. In the illustratedembodiment, the slots 310 may be assigned to narrow frequency sub-bandsand/or individual frequencies. In a non-limiting example, theillustrated slot 310 may be assigned to the frequency 100 Hz, or may beassigned to a narrow sub-band that includes 100 Hz, such as from 99 Hzto 101 Hz. In the illustrated embodiment, the frequency components 212of an acoustic signal that is transmitted through the time-sensitivenetwork 109 are assigned to various slots 310 based on the frequencies,but the frequency information is not transmitted with the frequencycomponents 212. For example, the frequency components 212 shown in FIG.4 contain information about the destination device and the amplitude.

Optionally, the frequency that is associated with the slot 310 may beselected based on a common or notable frequency within the acousticsignals that are conveyed through the network 109. For example, if afrequency component has a frequency of 99 Hz, then the slot 310 may beassigned to 99 Hz such that all frequency components 212 transmittedalong the slot 310 have the 99 Hz frequency. Alternatively, if the slot310 is associated with 100 Hz and an incoming frequency component of aninput acoustic signal has a frequency that is 99 Hz, then the system mayslightly degrade the quality of the signal by scheduling that frequencycomponent for transmission within the 100 Hz slot. Such a frequencycomponent will be interpreted by the listening device as having themodified frequency of 100 Hz, but the small discrepancy may beundetectable and therefore within a permissible error range.

In the illustrated embodiment, the acoustic signals are transmittedthrough the time-sensitive network 109 to a pair of receiving speakersthat play (e.g., emit) the acoustic signals. The destination device foreach frequency component 212 is one of the two speakers, either speakerA or speaker B. The frequency components 212 are scheduled to transmitat 10 millisecond (ms) transmission intervals 314 in FIG. 4, butdifferent intervals may be used in other embodiments. The firstfrequency component 212A that is transmitted at time 0 in the slot 310shows “B=1”, which indicates that the destination device is speaker B,and the amplitude of the given frequency is 1. The second frequencycomponent 212B that is transmitted at the second interval 314 startingat time 10 ms shows “A=0.5”, which indicates that the destination deviceis speaker A, and the amplitude of the given frequency is 0.5.

Additional reference is made to FIG. 5, which shows sine waves 360produced by the speaker A 362 and by the speaker B 364 according to theacoustic signals transmitted through the time-sensitive network 109 asthe frequency components 212 shown in FIG. 4. For example, upon receiptof the first frequency component 212A, speaker B is configured toimplement the signal by emitting a tone having the frequency associatedwith the slot 310 shown in FIG. 4 and the amplitude of 1. If theassociated frequency is 100 Hz, speaker B plays a tone with a 100 Hzfrequency and a 1 amplitude. The amplitude values may be based on areference amplitude or may have a unit such as decibels. Speaker A doesnot emit a tone during the first transmission interval 314 until time 10ms because the first frequency component 212A was addressed only tospeaker B. During the second transmission interval 314 that starts attime 10 ms, speaker A receives the second frequency component 212B andemits a tone having the designated frequency and the commanded amplitudeof 0.5. Speaker B continues to play the tone having the amplitude of 1until an additional command for speaker B is received. Therefore, duringthe second transmission interval, the sine waves 360 of speakers A and Bhave the same frequency, but the sine wave 360 of speaker B has agreater amplitude than the sine wave 360 of speaker A.

At 20 ms, the amplitude of the tone produced by speaker A increases to1.5 due to the receipt of a third frequency component 212C shown in FIG.4. No frequency component 212 is transmitted in the interval 314starting at 30 ms, so the speakers A and B continue to emit the samerespective tones during this interval 314 as the previous interval 314starting at 20 ms. At 40 ms, the frequency component 212 indicates thatspeaker B has an amplitude of 0, which explicitly stops speaker B fromproducing a tone at the designated frequency. Speaker A is alsoexplicitly stopped from producing the designated frequency at time 50ms. Therefore, after time 50 ms, neither speaker generates a tone havingthe designated frequency associated with the slot 310.

FIGS. 4 and 5 illustrate a single slot 310, but it is understood thatthe schedule 306 for the time-sensitive network 109 may schedule thetransmission of frequency components 212 of acoustic signals as shown inFIGS. 4 and 5 for each of the slots 310 of the frequency band 308 (shownin FIG. 3) to convey acoustic signals along different frequencies. Forexample, if the slot 310 shown in FIG. 4 is associated with thefrequency 100 Hz, then additional slots 310 associated with otherfrequencies such as 50 Hz, 25 Hz, 12.5 Hz, and/or the like may besimilarly scheduled to enable the speakers A and B to produce sounds(e.g., music) having multiple frequencies. The audio speaker device(e.g., receiver) that receives the acoustic signals from the network 109may be buffer-less because the speakers can simply play the amplitudesof the designated frequencies as the frequency components are receivedat the speaker device.

FIG. 6 illustrates a flowchart of one embodiment of a method 400 forcommunicating messages in a time-sensitive network onboard a vehiclesystem. The method 400 can represent operations performed by the controlsystem 107 (e.g., by the scheduler device 102) of the communicationsystem 100. Referring to FIGS. 1 through 5, at 402, a signal fidelitytarget is obtained. The signal fidelity target may be received by anoperator selection or accessed in a memory. The signal fidelity targetmay represent a degree of correspondence between a state of a signalexiting a time-sensitive network 109 at a listening device 106 and astate of the same signal entering the time-sensitive network 109 at apublishing device 106.

At 404, a schedule 306 is generated for transmission of signals withinthe time-sensitive network 109 onboard one or more locomotives 150. Theschedule 306 defines multiple slots 310 assigned to different discretefrequency sub-bands within a frequency band 308. The slots 310 havedesignated transmission intervals 314. The schedule 306 may be generatedin the frequency domain. For example, signals are transmitted throughthe network 109 based on frequency components 212 of the signals. Theschedule 306 is generated to satisfy the signal fidelity target. Forexample, the slots 310 may be assigned to a sufficient number offrequency sub-bands to satisfy the signal fidelity target. Optionally,the schedule 306 may be generated without utilizing one or moretime-based parameters, such as frame size and/or periodic latency, asconstraints. The schedule 306 may be generated such that thetime-sensitive network 109 functions as a low pass filter. For example,the frequency sub-bands assigned to the slots 310 may represent lessthan an entirety of the frequency band 308, and the time-sensitivenetwork 109 may not transmit frequency components 212 of signals thathave frequencies outside of the assigned sub-bands.

At 406, a signal 202 is obtained from a publishing device 106. Thesignal 202 is represented in the frequency domain by multiple frequencycomponents 212. The signal 202 may be one or more of an audio signal, anultrasound signal, a vibration signal, an audible sound signal, aninfrasound signal, or the like. The signal 202 may represent ameasurement of a component onboard the locomotive 150. The frequencycomponents 212 of the signal 202 may be encoded within Ethernet frames.

At 408, the frequency components 212 of the signal 202 are transmittedthrough the time-sensitive network 109 to a listening device 106according to the schedule 306. The time-sensitive network 109 includesvarious nodes 105 and communication links 103 between the nodes 105. Atleast some of the frequency components 212 of the signal 202 aretransmitted within different slots 310 of the schedule 306 based on thefrequency sub-bands assigned to the slots 310. For example, a firstfrequency component 212 of the signal 202 may be transmitted within afirst slot 310A of the schedule 306 assigned to a frequency sub-bandthat contains a frequency of the first frequency component 212. A secondfrequency component 212 of the signal 202 may be transmitted within asecond slot 310B of the schedule 306 assigned to a different frequencysub-band that contains a frequency of the second frequency component212. After transmission through the network 109, the different frequencycomponents 212 may be combined to form an intact signal 202 that isprovided to the listening device 106. The combination may includeconverting the signal 202 from a frequency-based representation to atime-based representation. The signal 202 received at the listeningdevice 106 may be used for controlling operations (e.g., movement) ofthe vehicle system.

In one or more embodiments, a vehicle-based communication system isprovided that transports frequency sub-band encoded signals through atime-sensitive network. The signals have a frequency content that mayinclude one or more of audio compressed signals, ultrasounds,vibrations, acoustic phenomena (e.g., acousto-optics), and/or the like.The use of time-aware scheduler devices on a time-sensitive network mayallow for reducing or omitting various signal compression and/orconversion steps, such as packing and unpacking compressed signals.

In a non-limiting example, a scheduler device can divide atime-sensitive network into a designated number of slots (e.g., 32slots) that are each assigned to a specific frequency sub-band. A slotmay be sent at a designated transmission interval, such as once every156 microseconds. The size of the slots can be adjusted to reflect thenumber of streams to be sent over the network. The size of the slots maybe calibrated. In a non-limiting example, 32 slots may be designatedthat each have a size of 2000 octets. For a 1 Gbps port, thecorresponding frequency band occupies 16 microseconds. The totalbandwidth consumed by the 32 slots is 512 microsecond. Assuming 5milliseconds as the maximal temporal resolution of a human ear, then itcorresponds to 10.24% of the available bandwidth.

The slot-specific size can be adjusted. For example, in audiocompression, frequencies close to 20 kHz are hardly detected by thehuman ear, and as such it can be expected that the frequency content isoften reduced. In this case, the slot size for frequencies close to 4kHz may be 2000 octets, while the slot size for frequencies close to 20kHz may be 256 octets, as defined by the user. This example can begeneralized to any application utilizing a time-sensitive network totransport frequency content that can be subdivided into sub-bands.

The time-aware scheduler device can be configured in such a way that itdrops a sample if it must be enqueued. For example, if a talker (e.g.,publishing device) is sending samples too fast for a specific sub-band,then compression is performed by the network itself, or, the network canbe considered as a low-pass filter. Generally, the bridge dropping asample detects the corresponding miss and can advertise to all thetalkers that lossy compression is being performed on a specific band.

The Ethernet frames may be at least 48 octets long (excluding theEthernet header). The stream ID can be used to represent the sample or asequence, and may use up to 8 octets. Out of the remaining 40 octets,the peaks of 5 frequencies can be represented in a given sub-band, with4 octets representing the frequency in its sub-band and 4 octets for itsamplitude. If quantization error is not damaging the quality too much,potentially 10 frequencies can be used. Different streams may be packedinto the same frame. In this case, the identifier can be used to makethe distinction.

The media clock may not be necessary if the listening device has atime-aware scheduler. The listening device keeps track of the number ofslots and multiplies it by the period (which equals to 5 milliseconds inour example) and then adds 156 microseconds per band id (for instance,1.56 milliseconds for the 10^(th) sub-band) to reconstruct the mediaclock. The audio signals may be subject to dispersion because each ofthe sub-bands is slightly delayed from each other, in our example by 156microseconds. Because the 156 microseconds is below the 5 millisecondmaximal temporal resolution of a human ear, the dispersion is notnoticeable.

Time-sensitive network generalized sub-band coding may be specifiedutilizing a quantification of signal error. In some use-cases, a goal isto transmit a signal in the frequency domain. In other use-cases, a goalis to transmit a signal coded in the frequency domain, but then toconvert to the time domain upon reception. In at least one embodiment,the scheduler device of the time-sensitive network is configured togenerate a schedule based on a quality-of-service (QoS) requirement orconstraint for sub-band coding. For example, the QoS requirement may bean objective function, and the scheduler device may compute an IEEE802.1Qbv configuration that meets the required QoS requirement. The QoSrequirement may represent or may be related to the signal fidelitytarget described herein.

A goal of one or more embodiments herein is to find a generalized meansof decoupling the implementation (the specific Qbv configuration) fromthe QoS measurement. This is beneficial because there may be multipleQbv configurations that yield the same QoS measurement. Forcing thetime-sensitive network to use a specific Qbv configuration, that is,specific frame size and maximum latency requirements, limits thesolution space of the scheduler device when more and better solutionsare available to meet a required QoS. According to at least oneembodiment, the scheduler device is configured to generate the scheduleto meet the general QoS requirement, and is not over-constrained byhaving to find a pre-ordained Qbv configuration. The scheduler devicemay be allowed to pick from any of a variety of satisfactory solutionsthat meet the QoS requirement. Qbv specifies data samples of a givenmaximum size into periodic sampling rates over a time-sensitive network.These may be samples from the time domain or from the frequency domain,such as specific frequency components. The QoS is the input to thescheduler device. The scheduler device may be free to choose anysolution that satisfies the higher-level QoS requirements, andoptionally is not given the maximum Ethernet frame size or maximumlatencies as constraints. This decoupling may allow for a largersolution space and a better solution. In an alternative, hybridapproach, all three of the QoS requirement, maximum frame sizes, andmaximum latencies are utilized as constraints when scheduling thetime-sensitive network.

With regards to the selection of which QoS measurement or requirement touse as the objective function, the QoS measurement generally must beable to map from a set of Ethernet frame sizes and periodic latencies(IEEE 802.1Qbv configuration) into a received signal quality. One optionis to use the power spectral density (PSD), which describes thedistribution of the average power of a signal over its frequencycomponents. The PSD might be useful in specifying the QoS in thefrequency domain or estimating how well the time domain wasreconstructed after transmission. Another option is to use mean opinionscores, which have been used for human sensual input, both audio andvisual. A third option is to use peak signal-to-noise ratio (PSNR),which can be automated to estimate video quality.

In an embodiment, a vehicle communication system includes multiple nodesof a time-sensitive network disposed onboard plural vehicles, and ascheduler device. The nodes are communicatively connected to each othervia wired and/or wireless links. At least one of the nodes is configuredto obtain a first signal from a publishing device. The first signal isrepresented in a frequency domain by multiple frequency components. Thescheduler device (e.g., comprising one or more processors) is configuredto generate a schedule for transmission of signals including the firstsignal within the time-sensitive network. The schedule defines multipleslots assigned to different discrete frequency sub-bands within afrequency band. The slots have designated transmission intervals. Thenodes are configured to transmit the first signal through thetime-sensitive network to a listening device such that the first signalis received at the listening device within a designated time windowaccording to the schedule. At least some of the frequency components ofthe first signal are transmitted through the time-sensitive networkwithin different slots of the schedule based on the frequency sub-bandsassigned to the slots. In one aspect, the plural vehicles aremechanically connected to one another, e.g., the vehicles may be railvehicles in a train. In another embodiment, the vehicles are notmechanically connected to one another, but are configured to wirelesslycommunicate signals over the network for coordinated control formovement together along a route.

In one embodiment, a communication system includes a scheduler deviceincluding one or more processors configured to generate a schedule forcommunication of signals through nodes of a time-sensitive network thatare communicatively connected to each other via links of thetime-sensitive network. At least a first signal of the signals isrepresented in a frequency domain by multiple frequency components andreceived into the time-sensitive network from a publishing device. Theone or more processors are configured to generate the schedule byassigning multiple slots having designated transmission intervals todifferent discrete frequency sub-bands within a frequency band. Theschedule is generated to direct the nodes to communicate the firstsignal from the publishing device through the time-sensitive network toa listening device such that the first signal is received at thelistening device within a designated time window according to theschedule. At least some of the frequency components of the first signalare transmitted through the time-sensitive network based on thefrequency sub-bands assigned to the slots.

Optionally, the one or more processors are configured to generate theschedule to direct the nodes to transmit a first frequency component ofthe first signal within a first slot of the slots that is assigned to afrequency sub-band that contains a frequency of the first frequencycomponent, and to transmit a second frequency component of the firstsignal within a second slot of the slots that is assigned to a differentfrequency sub-band that contains a frequency of the second frequencycomponent.

Optionally, the one or more processors are configured to determine adesignated signal fidelity target that represents a degree ofcorrespondence between an exit state of the first signal exiting thetime-sensitive network at the listening device and an entry state of thefirst signal entering the time-sensitive network at the publishingdevice. The one or more processors can be configured to generate theschedule to assign the slots to at least a number of the frequencysub-bands associated with the designated signal fidelity target.

Optionally, the one or more processors are configured to generate theschedule based on the designated signal fidelity target withoututilizing a frame size limit or a periodic latency limit as a constraintto the schedule.

Optionally, the one or more processors are configured to generate theschedule to assign less than all the frequency sub-bands of thefrequency band to the slots. The nodes can be configured to filter outone or more of the frequency components of the first signal having afrequency outside of the frequency sub-bands by transmitting only thefrequency components of the first signal having frequencies within thefrequency sub-bands assigned to the slots.

Optionally, the one or more processors are configured to generate theschedule to stagger the transmission intervals of the slots such that afirst frequency component of the first signal within a first slot istransmitted by the nodes of the time-sensitive network according to theschedule at different times than the nodes transmit a second frequencycomponent of the first signal within a second slot.

Optionally, the frequency components of the first signal are encodedwithin Ethernet frames. The Ethernet frames can include datarepresenting one or more of a frequency, an amplitude, or a phase ofeach of the frequency components encoded therein.

Optionally, the first signal is one or more of an audio signal, anultrasound signal, a vibration signal, an audible sound signal, and/oran infrasound signal.

Optionally, the one or more processors are configured to generate ormodify the schedule by changing a size of the frequency sub-bandassigned to one or more of the slots after the first signal istransmitted through the time-sensitive network.

Optionally, the publishing device is disposed onboard a first vehicleand the listening device is disposed one or more of onboard the firstvehicle, onboard a different, second vehicle, or at an off-boardlocation. The time-sensitive network is configured for use intransmitting the first signal one or more of onboard the first vehicle,between the first and second vehicles, or between the first vehicle andthe off-board location.

In one embodiment, a method includes generating a schedule fortransmission of signals within a time-sensitive network. The scheduledefines multiple slots assigned to different discrete frequencysub-bands within a frequency band and the slots have designatedtransmission intervals. The method also includes obtaining a firstsignal of the signals from a publishing device. The first signal isrepresented in a frequency domain by multiple frequency components. Themethod also includes transmitting the first signal through thetime-sensitive network to a listening device such that the first signalis received at the listening device within a designated time windowaccording to the schedule. At least some of the frequency components ofthe first signal are transmitted through the time-sensitive networkwithin different slots of the schedule based on the frequency sub-bandsassigned to the slots.

Optionally, transmitting the first signal through the time-sensitivenetwork includes transmitting a first frequency component of the firstsignal within a first slot of the schedule assigned to a frequencysub-band that contains a frequency of the first frequency component, andtransmitting a second frequency component of the first signal within asecond slot of the schedule assigned to a different frequency sub-bandthat contains a frequency of the second frequency component.

Optionally, the method also includes obtaining a designated signalfidelity target that represents correspondence between an exit state ofthe first signal exiting the time-sensitive network at the listeningdevice and an entry state of the first signal entering thetime-sensitive network at the publishing device. Generating the schedulemay include assigning the slots to a sufficient number of the frequencysub-bands to satisfy the designated signal fidelity target.

Optionally, the schedule is generated based on the designated signalfidelity target without utilizing a frame size limit or a periodiclatency limit as a constraint on the schedule.

Optionally, the frequency sub-bands assigned to the slots defined by theschedule represent less than an entirety of the frequency band.Transmitting the first signal can include transmitting only thefrequency components of the first signal having frequencies within thefrequency sub-bands assigned to the slots to filter out one or more ofthe frequency components of the first signal having a frequency outsideof the frequency sub-bands.

Optionally, generating the schedule comprises staggering thetransmission intervals of the slots such that a first frequencycomponent of the first signal within a first slot is transmitted by thenodes of the time-sensitive network according to the schedule atdifferent times than the nodes transmit a second frequency component ofthe first signal within a second slot.

Optionally, the frequency components of the first signal are encodedwithin Ethernet frames, and the Ethernet frames can include datarepresenting one or more of a frequency, an amplitude, and/or a phase ofeach of the frequency components encoded therein.

Optionally, the first signal is one or more of an audio signal, anultrasound signal, a vibration signal, an audible sound signal, and/oran infrasound signal.

Optionally, the method also includes combining the frequency componentsof the first signal after transmitting the frequency components throughthe time-sensitive network to provide an intact first signal to thelistening device.

Optionally, the publishing device is disposed onboard a first vehicleand the listening device is disposed one or more of onboard the firstvehicle, onboard a different, second vehicle, or at an off-boardlocation. Transmitting the first signal through the time-sensitivenetwork includes transmitting the first signal one or more of onboardthe first vehicle, between the first and second vehicles, or between thefirst vehicle and the off-board location.

In one embodiment, a communication system includes a scheduler deviceincluding one or more processors configured to generate a schedule forcommunication of signals through nodes of a time-sensitive network thatare communicatively connected to each other via links of thetime-sensitive network. At least a first signal of the signals isrepresented in a frequency domain by multiple frequency components andreceived into the time-sensitive network from a publishing device. Theone or more processors are configured to generate the schedule byassigning multiple slots having designated transmission intervals todifferent discrete frequency sub-bands within a frequency band. Theschedule is generated to direct the nodes to communicate the frequencycomponents of the first signal through the time-sensitive network basedon the frequency sub-bands assigned to the slots such that the nodestransmit a first frequency component of the first signal within a firstslot of the slots that is assigned to a frequency sub-band that containsa frequency of the first frequency component and the nodes transmit asecond frequency component of the first signal within a second slot ofthe slots that is assigned to a different frequency sub-band thatcontains a frequency of the second frequency component.

Optionally, the one or more processors are configured to generate ormodify the schedule by changing a size of the frequency sub-bandassigned to one or more of the slots after the first signal istransmitted through the time-sensitive network.

Optionally, the publishing device is disposed onboard a first vehicleand the first signal is transmitted through the time-sensitive networkto a listening device disposed one or more of onboard the first vehicle,onboard a different, second vehicle, or at an off-board location. Thetime-sensitive network is configured for use in transmitting the firstsignal one or more of onboard the first vehicle, between the first andsecond vehicles, or between the first vehicle and the off-boardlocation.

In an embodiment, a rail vehicle communication system is provided thatincludes multiple nodes of a time-sensitive network and a schedulerdevice. The time-sensitive network is disposed onboard one or morelocomotives. The nodes are communicatively connected to each other vialinks. At least one of the nodes is configured to obtain a first signalfrom a publishing device. The first signal is represented in a frequencydomain by multiple frequency components. The scheduler device comprisesone or more processors and is configured to generate a schedule fortransmission of signals including the first signal within thetime-sensitive network. The schedule defines multiple slots assigned todifferent discrete frequency sub-bands within a frequency band. Theslots have designated transmission intervals. The nodes are configuredto transmit the first signal through the time-sensitive network to alistening device such that the first signal is received at the listeningdevice within a designated time window according to the schedule. Atleast some of the frequency components of the first signal aretransmitted through the time-sensitive network within different slots ofthe schedule based on the frequency sub-bands assigned to the slots.

Optionally, the nodes are configured to transmit a first frequencycomponent of the first signal within a first slot of the scheduleassigned to a frequency sub-band that contains a frequency of the firstfrequency component, and the nodes transmit a second frequency componentof the first signal within a second slot of the schedule assigned to adifferent frequency sub-band that contains a frequency of the secondfrequency component.

Optionally, the scheduler device is configured to obtain a designatedsignal fidelity target that represents a degree of correspondencebetween a state of the first signal exiting the time-sensitive networkat the listening device and a state of the first signal entering thetime-sensitive network at the publishing device. The scheduler devicegenerates the schedule to assign the slots to a sufficient number of thefrequency sub-bands to satisfy the designated signal fidelity target.Optionally, the scheduler device is configured to generate the schedulebased on the designated signal fidelity target without utilizing a framesize limit or a periodic latency limit as a constraint.

Optionally, the frequency sub-bands assigned to the slots defined by theschedule represent less than an entirety of the frequency band. Thenodes are configured to transmit only the frequency components of thefirst signal having frequencies within the frequency sub-bands assignedto the slots to filter out one or more of the frequency components ofthe first signal having a frequency outside of the frequency sub-bands.

Optionally, the scheduler device is configured to generate the scheduleto stagger the transmission intervals of the slots such that a firstfrequency component of the first signal within a first slot istransmitted by nodes of the time-sensitive network according to theschedule at different times than the nodes transmit a second frequencycomponent of the first signal within a second slot.

Optionally, the frequency components of the first signal are encodedwithin Ethernet frames, and the Ethernet frames include datarepresenting a frequency, an amplitude, and/or a phase of each of thefrequency components encoded therein.

Optionally, the first signal is an audio signal, an ultrasound signal, avibration signal, an audible sound signal, and/or an infrasound signal.

Optionally, the first signal represents a measurement of a componentonboard a first locomotive of the one or more locomotives.

Optionally, the scheduler device is further configured to modify a sizeof the frequency sub-band assigned to one or more of the slots after thefirst signal is transmitted through the time-sensitive network.

In an embodiment, a method for locomotive communications is providedthat includes generating a schedule for transmission of signals within atime-sensitive network onboard one or more locomotives. The scheduledefines multiple slots assigned to different discrete frequencysub-bands within a frequency band. The slots have designatedtransmission intervals. The method includes obtaining a first signal ofthe signals from a publishing device. The first signal is represented ina frequency domain by multiple frequency components. The method alsoincludes transmitting the first signal through the time-sensitivenetwork to a listening device such that the first signal is received atthe listening device within a designated time window according to theschedule. At least some of the frequency components of the first signalare transmitted through the time-sensitive network within differentslots of the schedule based on the frequency sub-bands assigned to theslots.

Optionally, transmitting the first signal through the time-sensitivenetwork includes transmitting a first frequency component of the firstsignal within a first slot of the schedule assigned to a frequencysub-band that contains a frequency of the first frequency component, andtransmitting a second frequency component of the first signal within asecond slot of the schedule assigned to a different frequency sub-bandthat contains a frequency of the second frequency component.

Optionally, the method also includes obtaining a designated signalfidelity target that represents a degree of correspondence between astate of the first signal exiting the time-sensitive network at thelistening device and a state of the first signal entering thetime-sensitive network at the publishing device. Generating the schedulecomprises assigning the slots to a sufficient number of the frequencysub-bands to satisfy the designated signal fidelity target. Optionally,the schedule is generated based on the designated signal fidelity targetwithout utilizing a frame size limit or a periodic latency limit as aconstraint.

Optionally, the frequency sub-bands assigned to the slots defined by theschedule represent less than an entirety of the frequency band.Transmitting the first signal comprises transmitting only the frequencycomponents of the first signal having frequencies within the frequencysub-bands assigned to the slots to filter out one or more of thefrequency components of the first signal having a frequency outside ofthe frequency sub-bands.

Optionally, generating the schedule comprises staggering thetransmission intervals of the slots such that a first frequencycomponent of the first signal within a first slot is transmitted bynodes of the time-sensitive network according to the schedule atdifferent times than the nodes transmit a second frequency component ofthe first signal within a second slot.

Optionally, the frequency components of the first signal are encodedwithin Ethernet frames, and the Ethernet frames includes datarepresenting a frequency, an amplitude, and/or a phase of each of thefrequency components encoded therein.

Optionally, the first signal is an audio signal, an ultrasound signal, avibration signal, an audible sound signal, and/or an infrasound signal.

Optionally, the method also includes combining the frequency componentsof the first signal after transmitting the frequency components throughthe time-sensitive network to provide an intact first signal to thelistening device.

Optionally, the first signal represents a measurement of a componentonboard a first locomotive of the one or more locomotives.

Optionally, the method also includes modifying a size of the frequencysub-band assigned to one or more of the slots after transmitting thefirst signal through the time-sensitive network.

As used herein, an element or step recited in the singular and proceededwith the word “a” or “an” should be understood as not excluding pluralof said elements or steps, unless such exclusion is explicitly stated.Furthermore, references to “one embodiment” of the presently describedsubject matter are not intended to be interpreted as excluding theexistence of additional embodiments that also incorporate the recitedfeatures. Moreover, unless explicitly stated to the contrary,embodiments “comprising,” “including,” and “having” an element or aplurality of elements with a particular property may include additionalsuch elements not having that property.

It is to be understood that the above description is intended to beillustrative, and not restrictive. For example, the above-describedembodiments (and/or aspects thereof) may be used in combination witheach other. In addition, many modifications may be made to adapt aparticular situation or material to the teachings of the subject matterset forth herein without departing from its scope. While the dimensionsand types of materials described herein are intended to define theparameters of the disclosed subject matter, they are by no meanslimiting and are example embodiments. Many other embodiments will beapparent to those of ordinary skill in the art upon reviewing the abovedescription. The scope of the subject matter described herein should,therefore, be determined with reference to the appended claims, alongwith the full scope of equivalents to which such claims are entitled. Inthe appended claims, the terms “including” is used as the plain-Englishequivalents of the term “comprising.” Moreover, in the following claims,the terms “first,” “second,” and “third,” etc. are used merely aslabels, and are not intended to impose numerical requirements on theirobjects. Further, the limitations of the following claims are notwritten in means-plus-function format and are not intended to beinterpreted based on 35 U.S.C. § 112(f), unless and until such claimlimitations expressly use the phrase “means for” followed by a statementof function void of further structure.

What is claimed is:
 1. A communication system comprising: a schedulerdevice including one or more processors configured to generate aschedule for communication of signals through nodes of a time-sensitivenetwork that are communicatively connected to each other via links ofthe time-sensitive network, at least a first signal of the signalsrepresented in a frequency domain by multiple frequency components andreceived into the time-sensitive network from a publishing device,wherein the one or more processors are configured to generate theschedule by assigning multiple slots having designated transmissionintervals to different discrete frequency sub-bands within a frequencyband, wherein the schedule is generated to direct the nodes tocommunicate the first signal from the publishing device through thetime-sensitive network to a listening device such that the first signalis received at the listening device within a designated time windowaccording to the schedule, wherein at least some of the frequencycomponents of the first signal are transmitted through thetime-sensitive network based on the frequency sub-bands assigned to theslots.
 2. The communication system of claim 1, wherein the one or moreprocessors are configured to generate the schedule to direct the nodesto transmit a first frequency component of the first signal within afirst slot of the slots that is assigned to a frequency sub-band thatcontains a frequency of the first frequency component, and to transmit asecond frequency component of the first signal within a second slot ofthe slots that is assigned to a different frequency sub-band thatcontains a frequency of the second frequency component.
 3. Thecommunication system of claim 1, wherein the one or more processors areconfigured to determine a designated signal fidelity target thatrepresents a degree of correspondence between an exit state of the firstsignal exiting the time-sensitive network at the listening device and anentry state of the first signal entering the time-sensitive network atthe publishing device, wherein the one or more processors are configuredto generate the schedule to assign the slots to at least a number of thefrequency sub-bands associated with the designated signal fidelitytarget.
 4. The communication system of claim 3, wherein the one or moreprocessors are configured to generate the schedule based on thedesignated signal fidelity target without utilizing a frame size limitor a periodic latency limit as a constraint to the schedule.
 5. Thecommunication system of claim 1, wherein the one or more processors areconfigured to generate the schedule to assign less than all thefrequency sub-bands of the frequency band to the slots, wherein thenodes are configured to filter out one or more of the frequencycomponents of the first signal having a frequency outside of thefrequency sub-bands by transmitting only the frequency components of thefirst signal having frequencies within the frequency sub-bands assignedto the slots.
 6. The communication system of claim 1, wherein the one ormore processors are configured to generate the schedule to stagger thetransmission intervals of the slots such that a first frequencycomponent of the first signal within a first slot is transmitted by thenodes of the time-sensitive network according to the schedule atdifferent times than the nodes transmit a second frequency component ofthe first signal within a second slot.
 7. The communication system ofclaim 1, wherein the frequency components of the first signal areencoded within Ethernet frames, the Ethernet frames including datarepresenting one or more of a frequency, an amplitude, or a phase ofeach of the frequency components encoded therein.
 8. The communicationsystem of claim 1, wherein the first signal is one or more of an audiosignal, an ultrasound signal, a vibration signal, an audible soundsignal, or an infrasound signal.
 9. The communication system of claim 1,wherein the one or more processors are configured to generate or modifythe schedule by changing a size of the frequency sub-band assigned toone or more of the slots after the first signal is transmitted throughthe time-sensitive network.
 10. The communication system of claim 1,wherein the publishing device is disposed onboard a first vehicle andthe listening device is disposed one or more of onboard the firstvehicle, onboard a different, second vehicle, or at an off-boardlocation such that the time-sensitive network is configured for use intransmitting the first signal one or more of onboard the first vehicle,between the first and second vehicles, or between the first vehicle andthe off-board location.
 11. A method comprising: generating a schedulefor transmission of signals within a time-sensitive network, wherein theschedule defines multiple slots assigned to different discrete frequencysub-bands within a frequency band, the slots having designatedtransmission intervals; obtaining a first signal of the signals from apublishing device, the first signal represented in a frequency domain bymultiple frequency components; and transmitting the first signal throughthe time-sensitive network to a listening device such that the firstsignal is received at the listening device within a designated timewindow according to the schedule, wherein at least some of the frequencycomponents of the first signal are transmitted through thetime-sensitive network within different slots of the schedule based onthe frequency sub-bands assigned to the slots.
 12. The method of claim11, wherein transmitting the first signal through the time-sensitivenetwork includes transmitting a first frequency component of the firstsignal within a first slot of the schedule assigned to a frequencysub-band that contains a frequency of the first frequency component, andtransmitting a second frequency component of the first signal within asecond slot of the schedule assigned to a different frequency sub-bandthat contains a frequency of the second frequency component.
 13. Themethod of claim 11, further comprising: obtaining a designated signalfidelity target that represents correspondence between an exit state ofthe first signal exiting the time-sensitive network at the listeningdevice and an entry state of the first signal entering thetime-sensitive network at the publishing device, wherein generating theschedule comprises assigning the slots to a sufficient number of thefrequency sub-bands to satisfy the designated signal fidelity target.14. The method of claim 13, wherein the schedule is generated based onthe designated signal fidelity target without utilizing a frame sizelimit or a periodic latency limit as a constraint on the schedule. 15.The method of claim 11, wherein the frequency sub-bands assigned to theslots defined by the schedule represent less than an entirety of thefrequency band, wherein transmitting the first signal comprisestransmitting only the frequency components of the first signal havingfrequencies within the frequency sub-bands assigned to the slots tofilter out one or more of the frequency components of the first signalhaving a frequency outside of the frequency sub-bands.
 16. The method ofclaim 11, wherein generating the schedule comprises staggering thetransmission intervals of the slots such that a first frequencycomponent of the first signal within a first slot is transmitted by thenodes of the time-sensitive network according to the schedule atdifferent times than the nodes transmit a second frequency component ofthe first signal within a second slot.
 17. The method of claim 11,further comprising: combining the frequency components of the firstsignal after transmitting the frequency components through thetime-sensitive network to provide an intact first signal to thelistening device.
 18. The method of claim 11, wherein the publishingdevice is disposed onboard a first vehicle and the listening device isdisposed one or more of onboard the first vehicle, onboard a different,second vehicle, or at an off-board location such that transmitting thefirst signal through the time-sensitive network includes transmittingthe first signal one or more of onboard the first vehicle, between thefirst and second vehicles, or between the first vehicle and theoff-board location.
 19. A communication system comprising: a schedulerdevice including one or more processors configured to generate aschedule for communication of signals through nodes of a time-sensitivenetwork that are communicatively connected to each other via links ofthe time-sensitive network, at least a first signal of the signalsrepresented in a frequency domain by multiple frequency components andreceived into the time-sensitive network from a publishing device,wherein the one or more processors are configured to generate theschedule by assigning multiple slots having designated transmissionintervals to different discrete frequency sub-bands within a frequencyband, wherein the schedule is generated to direct the nodes tocommunicate the frequency components of the first signal through thetime-sensitive network based on the frequency sub-bands assigned to theslots such that the nodes transmit a first frequency component of thefirst signal within a first slot of the slots that is assigned to afrequency sub-band that contains a frequency of the first frequencycomponent and the nodes transmit a second frequency component of thefirst signal within a second slot of the slots that is assigned to adifferent frequency sub-band that contains a frequency of the secondfrequency component.
 20. The communication system of claim 19, whereinthe one or more processors are configured to generate or modify theschedule by changing a size of the frequency sub-band assigned to one ormore of the slots after the first signal is transmitted through thetime-sensitive network.